In the European Patent Publication No. 156,433 published Oct. 2, 1985, which corresponds to U.S. Ser. No. 702,772, there are described antivirally active pyridazinamines. Further antiviral agents are described in U.S. Pat. No. 4,451,476 and in the European Patent Publication No. 137,242 published Apr. 17, 1985 both containing invariably an isoxazole moiety.
The compounds of the present invention differ from the cited art compounds by the fact that they contain a pyridazinamine moiety which is substituted in a previously undisclosed manner and particularly by their favourable antiviral properties.